The present invention relates to a positioning means and a press-sealing means. They are used, for example, in a fill-and-pack in a non-germ atmosphere machine in which sterilization of containers, filling of food and packing are completed automatically while the containers are carried on a pair of rails. In this machine, the positioning means sets each container's position and supports it from underneath when a lid is pressed and sealed on the container by the press-sealing means.
First, the background of the positioning means will be explained below.
Fresh foods, especially such as dairy products, are preferably filled and packed in a non-germ atmosphere because they rot by germs in a short time. Japanese Utility Model Provisional Publication No. 61-53306 and Japanese Patent Provisional Publication No. 59-115221 introduces machines in which filling and packing dairy foods in a non-germ atmosphere can be done.
In these prior arts, a large number of holder plates are firmly tightened to a conveyer and each of them holds a container in a hole formed therein. The containers are carried as the conveyer moves, and the filling and the packing processes are completed while the position of each container is adjusted by the holder plates.
This type of machine is considerably effective when it is used as such that a same kind of food is filled in certain sized containers for a long time. However, this machine is not effective when it is used for an operation to fill different kinds of foods into different sized containers, each in a short time, such as filling plain yogurt into small containers one week and filling fruit yogurt into bigger containers the next week and so forth. In this machine, when the containers are to be replaced by other sized ones, the holder plates also have to be replaced by others because they cannot hold different sized containers. The holder plates of this machine are tightened to the conveyer by bolts and nuts, so that it takes a lot of time and hard work to replace the holder plates. It is necessary to loosen and then tighten the bolts and nuts for the holder plates. Further, it is also necessary to adjust the position of each holder plate after it is tightened to the conveyer.
Concerning the problems the prior art has, the inventors created a new art that does not comprise holder plates. Instead, it has at least a pair of rails. Containers are hung on the rails by their flanges and are intermittently carried by comb-like teeth that makes a square locus movement.
In this new art, since the containers are hung freely on the rails, adjusting a position of each container and supporting it from underneath are essential when a lid is provided and a hot press sealing thereon is accomplished.
Therefore, the first object of the present invention is to provide a positioning means that sets each container's proper position and gives the container enough strength by supporting it from underneath when a lid is sealed on the container.
Second, the background of the press-sealing means will be explained below.
In a prior art of sealing a seat-like lid on top of a container, a means that heats, presses and seals a lid on top of the container while a flange of the container is supported from underneath is known.
In this kind of means, as shown in FIG. 12, a pressing unit is shakably installed. It is because a thickness of a flange slightly differs depending on a container, some are noticeably deformed. Therefore, in many cases, the undersurface of the pressing unit and the top surface of a container are not parallel. In such a case, a lid could slide on the container since only projected parts of the container is pressed.
Concerning this problem, the prior art shown in FIG. 12 is arranged such that the top center of the pressing unit 43 is pressed by springs 68 while it is supported by hold bars 69, and the presssing unit 43 presses the top surface of a container. In case the top surface of the container is inclined, thus not being parallel to the pressing unit 43, the pressing unit 43 inclines and presses possibly the whole surface of the lid 39.
The problem of the prior art, however, is that a lid on a container could slide from its proper position.
This happens because the top surface of the pressing unit 43 is pushed by a means such as a cylinder. If the pressing unit 43 inclines .theta. degrees, a sliding gap (X) of the pressing unit 43 is described as X=l.multidot.sin .theta.. l is a distance between the top surface, the point that is pressed by the cylinder, and the undersurface of the pressing unit 43. The sliding gap (X) is proportional to the distance (l).
When a container is sealed by a lid by this prior art, the pressing unit 43 moves down and touches the lid placed on top of the container. As the pressing unit 43 continues to move down, it pushes the lid more downwardly and begins to incline to the same direction the top surface of the container is inclined. The inclination of the pressing unit 43 can be achieved as its undersurface slides in a side direction. By this movement, the lid pushed by the pressing unit 43 will slide with the pressing unit 43 and it will be sealed on the container improperly.
Also, when a so-called ring seal--a ring-like projection and a seal land are provided to the undersurface of the pressing unit and top of a container respectively, and sealing is accomplished by attaching the both--is concerned, the sealing cannot properly be done since the pressing unit slides and the ring-like projection (the pressing surface) slides from the seal land.
The same thing can be said when this prior art is used for a so-called hot-stamp. When the hot-stamp is applied for example on the surface of a box by placing a printing seat thereon, the printing seat could slide since the pressing unit slides and pushes the printing seat in a side direction.
Therefore, another object of the present invention is to present a press-sealing means that will not slide a lid or a printing seat on such as a container or a box, and accomplishes an accurate hot sealing or hot-stamping.